JP2015515084A5

JP2015515084A5 -

Info

Publication number: JP2015515084A5
Application number: JP2014559277A
Authority: JP
Filing date: 2013-02-27
Publication date: 2017-08-17
Anticipated expiration: 2033-02-27

Description

本発明は活物質として硫酸塩を含有する電極材料に関し、またその製造法に関する。 The present invention relates to an electrode material containing sulfate as an active material, and to a method for producing the same.

本発明の目的は、アルカリ金属および＋ＩＩ酸化状態の鉄を含有する新規電極材料を提供することであって、該材料はフッ素を含まないにも拘わらず高い動作電位を有する。さらに、当該材料を信頼性の高い、迅速かつ経済的な方法で当該材料の製造を可能とするプロセスを提供することである。 An object of the present invention, comprises providing a novel electrode material containing iron of alkali metals and + II oxidation state, the material has a high operating potential despite containing no fluorine. Further, to provide a process which enables the production of the material the material reliable, fast and economical way.

本発明による電極材料は、陽極電極活物質として、式（Ｎａ_１−ａＬｉ_ｂ）_ｘＦｅ_ｙ（ＳＯ_４）_ｚ（Ｉ）に相当する＋ＩＩ酸化状態の鉄とアルカリ金属の少なくとも１種の硫酸塩を含むことを特徴とする（式中、下付き文字ａ、ｂ、ｘ、ｙおよびｚは該化合物の電気的中性を保証するように選択され、０≦ａ≦１、０≦ｂ≦１、１≦ｘ≦３、１≦ｙ≦２、１≦ｚ≦３、および２≦（２ｚ−ｘ）／ｙ＜３であり、その結果、鉄の少なくとも１部分が＋ＩＩ酸化状態となる。ただし、陽極の活物質としての使用がすでに記載されている化合物Ｌｉ_２Ｆｅ_２（ＳＯ_４）_３（取り分け、欧州特許出願公開第０，７４３，６９２号明細書のもの）は除外する）。 The electrode material according to the present invention comprises, as an anode active material, at least one sulfuric acid of iron and alkali metal in the + II oxidation state corresponding to the formula (Na _1-a Li _b ) _x Fe _y (SO ₄ ) _z (I) Wherein the subscripts a, b, x, y and z are selected to ensure the electrical neutrality of the compound, 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, 1 ≦ x ≦ 3, 1 ≦ y ≦ 2, 1 ≦ z ≦ 3, and 2 ≦ (2z−x) / y <3, so that at least a portion of iron is in the + II oxidation state. However, the compound Li ₂ Fe ₂ (SO ₄ ) ₃ (particularly, from European Patent Application No. 0,743,692) whose use as the active material of the anode has already been described is excluded).

本発明の電極材料は、好ましくは、式（Ｉ）の化合物を少なくとも５０重量％、より好ましくは、少なくとも８０重量％含有する。 The electrode material of the present invention preferably contains at least 50% by weight, more preferably at least 80% by weight of the compound of formula (I).

特に好適な一実施形態において、該電極材料は電子伝導剤、および選択肢としてバインダをも含有する。 In a particularly preferred embodiment, the electrode material also contains an electron conducting agent and optionally a binder.

本発明による電極材料において活物質として使用される式（Ｉ）の硫酸塩は、化合物Ｌｉ_２Ｆｅ_２（ＳＯ_４）_３を例外として新規であるが、しかしこの化合物も直接合成によってこれまでに得られていない（すなわち、化合物Ｆｅ_２（ＳＯ_４）_３の還元による以外）。この点で、それらは本発明のもう一つの対象を構成する。 The sulfate of formula (I) used as active material in the electrode material according to the invention is novel with the exception of the compound Li ₂ Fe ₂ (SO ₄ ) ₃ , but this compound has also been obtained by direct synthesis so far. (Ie, not by reduction of the compound Fe ₂ (SO ₄ ) ₃ ). In this respect, they constitute another subject of the present invention.

上記の式（Ｉ）の硫酸塩で、本発明の電極材料の活物質として特に有利なものの内、取り分け言及し得るのは、Ｌｉ_２Ｆｅ（ＳＯ_４）_２、Ｎａ_２Ｆｅ（ＳＯ_４）_２および式（Ｉ’）（Ｎａ_１−ａＬｉ_ｂ）_ｘＦｅ（ＳＯ_４）_２（式中、１≦ｘ≦３であり、さらに０＜ａ＜１および０＜ｂ＜１）で示される混合硫酸塩である。 Among the sulfates of the above formula (I), among the particularly advantageous active materials of the electrode material of the present invention, mention may be made of Li ₂ Fe (SO ₄ ) _{2 and} Na ₂ Fe (SO ₄ ) _2. And the formula (I ′) (Na _1−a Li _b ) _x Fe (SO ₄ ) ₂ (where 1 ≦ x ≦ 3, and further 0 <a <1 and 0 <b <1) Sulfate.

本発明による化合物（Ｉ）を含有する電極材料は種々の電気化学装置に使用し得る。例示すると、本発明の電極材料は、電解液中のアルカリ金属イオン（Ｌｉ^＋またはＮａ^＋）の循環により作動する電気化学装置（例えば、特にバッテリー、スーパーコンデンサおよびエレクトロクロミックシステム）の電極の製造に使用し得る。 The electrode material containing the compound (I) according to the present invention can be used in various electrochemical devices. Illustratively, the electrode material of the present invention is suitable for the production of electrodes for electrochemical devices (eg, especially batteries, supercapacitors and electrochromic systems) that operate by the circulation of alkali metal ions (Li ⁺ or Na ⁺ ) in the electrolyte. Can be used.

本発明による電極材料を含有する電極は、式（Ｉ）の硫酸塩を含有する陽極組成物を集電体上に堆積させることにより調製し得る。当該組成物は好ましくは電子伝導剤、および選択肢としてバインダをも含有する。当該組成物における硫酸塩含有率は、好ましくは少なくとも５０重量％であり、より好ましくは少なくとも８０重量％である。電子伝導剤の含有率は１５重量％未満であり、バインダの含有率は１０％未満である。 An electrode containing an electrode material according to the present invention may be prepared by depositing an anode composition containing a sulfate of formula (I) on a current collector. The composition preferably also contains an electronic conductor and, optionally, a binder. The sulfate content in the composition is preferably at least 50% by weight, more preferably at least 80% by weight. The content of the electron conductive agent is less than 15% by weight, and the content of the binder is less than 10%.

作用電極の材料がポリマー系バインダを含有している場合は、式（Ｉ）の硫酸塩、バインダ、揮発性溶媒、および選択肢としてのイオン伝導剤を含有する組成物を調製し、当該組成物を集電体上に塗布し、乾燥によって揮発性溶媒を除去するのが有利である。揮発性溶媒とは、例えば、アセトン、テトラヒドロフラン、ジエチルエーテル、ヘキサンおよびＮ−メチルピロリドンから選択し得る。 If the working electrode material contains a polymeric binder, a composition containing a sulfate of formula (I), a binder, a volatile solvent, and an optional ionic conductor is prepared and the composition is It is advantageous to apply on the current collector and remove the volatile solvent by drying. The volatile solvent can be selected from, for example, acetone, tetrahydrofuran, diethyl ether, hexane and N-methylpyrrolidone.

集電体上に堆積させる材料の量は、好ましくは、本発明による化合物の量が１ｃｍ^２当り０．１ないし２００ｍｇ、好ましくは１ｃｍ^２当り１ないし５０ｍｇとなるようにする。集電体は、アルミニウム、チタン、黒鉛ペーパー、またはステンレス鋼からなるものであってもよい。 The amount of material to be deposited on the current collector, preferably, to the amount of the compound according to the invention 1 cm ² per 0.1 200mg, preferably made to be 50mg to 1 cm ² per 1. The current collector may be made of aluminum, titanium, graphite paper, or stainless steel.

Claims

An anode material having the formula (Na _1-a Li _b ) _x Fe _y (SO ₄ ) _z (I) (where the subscripts a, b, x, y and z are the compounds Of 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, 1 ≦ x ≦ 3, 1 ≦ y ≦ 2, 1 ≦ z ≦ 3, and 2 ≦ (2z−x). ) / Y <3, so that at least a portion of the iron is in the + II oxidation state, except for the compound Li ₂ Fe ₂ (SO ₄ ) ₃ ). Contains sulfates composed of iron and alkali metals ,
Furthermore, it contains an electron conductive agent and a binder,
The sulfates of formula (I) are Li ₂ Fe (SO ₄ ) ₂ , Na ₂ Fe (SO ₄ ) ₂ , and formula (I ′) (Na _1-a Li _b ) _x Fe (SO ₄ ) _2. Selected from mixed sulfates, wherein 1 ≦ x ≦ 3 and 0 <a <1 and 0 <b <1
Anode material content of the binder, characterized in der Rukoto less than 10 wt%.

2. Material according to claim 1, characterized in that it contains at least 50% by weight of the sulfate of formula (I).

A method of manufacturing an electrode containing a material as claimed in 請 Motomeko 1 or 2, and sulfates of formula (I), an electron conducting material, a positive electrode composition contains a binder the Depositing a composition having a binder content of less than 10% by weight on a current collector .

Claim the content of sulfate in the composition is at least 50 wt%, the content of the electron conductive agent is less than 15 wt%, the content of the binder and less than 10 wt% 3. The method according to 3 .

The method according to claim 3 or 4 , wherein the electron conducting agent is carbon black, acetylene black, natural or synthetic graphite, or carbon nanotube.

5. The binder according to claim 3 or 4 , characterized in that the binder is a polymer selected from fluoropolymers, carboxymethylcellulose and copolymers of ethylene and propylene, or a blend of at least two of these polymers. Way .

A process for producing a sulfate of formula ( I ) starting from lithium sulfate, sodium sulfate and iron sulfate,
Mixing the sulfate precursor with an amount corresponding to the stoichiometry of the sulfate of formula (I);
Heat-treating the mixture at a temperature of 100 ° C. to 350 ° C. in an inert atmosphere or a reducing atmosphere;
4. The method of claim 3, comprising :

A process for producing a sulfate of formula ( I ) starting from lithium sulfate, sodium sulfate and iron sulfate,
Mixing the sulfate precursor with an amount corresponding to the stoichiometry of the sulfate of formula (I);
Suspending the sulfate mixture in an ionic liquid;
Heat treating the suspension at a temperature between 100 ° C. and the stability limit temperature of the ionic liquid;
4. The method of claim 3, comprising :

From the formula Na _{x ′} Fe _y (SO ₄ ) _z electrochemically converted to a sulfate of formula ( I ) , wherein y and z are as defined for the sulfate of formula (I). A method of starting and manufacturing,
Carrying out the method in an electrochemical cell in which the active material of the anode is the compound Na _{x ′} Fe _y (SO ₄ ) _z , the anode contains lithium and the electrolyte contains a lithium salt;
Subjecting the electrochemical cell to a charge / discharge cycle;
The method according to claim 3 .

From the formula Li _{x ′} Fe _y (SO ₄ ) _z electrochemically converted to the sulfate of formula ( I ), where y and z are as defined for the sulfate of formula (I). A method of starting and manufacturing,
Carrying out the method in an electrochemical cell in which the active material of the anode is the compound Li _{x ′} Fe _y (SO ₄ ) _z , the anode contains sodium and the electrolyte contains a sodium salt;
Subjecting the electrochemical cell to a charge / discharge cycle;
The method according to claim 3 .